When \( f\left(x \right)=x \) , from proof of Theorem 3.2 in [1]}, they get an equation
\( 0=\left| \left[{\bf \Omega }_{M}\left( \phi _{k}\right) \right] _{kk}+\mathrm { lim}\gamma _{kj}\left\lbrace \phi _{k}^{2}\underline{m}_{2}(\phi _{k})\right\rbrace {\bf I}_{m_{k}}\right|\) 
